master 8232325: Handle case where a face's :extend attribute is unspecified (Bug#37774)

[Martin Rudalics]

branch: master
commit 82323253378c310c71cfea393d228321d1fc51f4
Author: Jimmy Aguilar Mena <address@hidden>
Commit: Martin Rudalics <address@hidden>

    Handle case where a face's :extend attribute is unspecified (Bug#37774)
    
    * src/xfaces.c (merge_face_vectors, merge_named_face): Handle case
    where the :extend attribute's value is 'unspecified' (Bug#37774).
---
 src/xfaces.c | 14 ++++++++++----
 1 file changed, 10 insertions(+), 4 deletions(-)

diff --git a/src/xfaces.c b/src/xfaces.c
index 3806fa9..67fa9e2 100644
--- a/src/xfaces.c
+++ b/src/xfaces.c
@@ -2062,8 +2062,13 @@ merge_face_vectors (struct window *w, struct frame *f,
 
   eassert (attr_filter <  LFACE_VECTOR_SIZE);
 
-  /* When FROM sets attr_filter to nil explicitly we don't merge it.  */
-  if (attr_filter > 0 && NILP(from[attr_filter]))
+  /* When FROM sets attr_filter explicitly to nil or unspecified
+     without inheriting don't merge it.  */
+  if (attr_filter > 0
+      && (NILP(from[attr_filter])
+         || (UNSPECIFIEDP(from[attr_filter])
+             && (NILP (from[LFACE_INHERIT_INDEX])
+                 || UNSPECIFIEDP (from[LFACE_INHERIT_INDEX])))))
     return;
 
   /* If FROM inherits from some other faces, merge their attributes into
@@ -2082,7 +2087,7 @@ merge_face_vectors (struct window *w, struct frame *f,
       else if (UNSPECIFIEDP (from[attr_filter])) /* FROM don't specify filter 
*/
        {
          Lisp_Object tmp[LFACE_VECTOR_SIZE];
-         memcpy (tmp, to, LFACE_VECTOR_SIZE * sizeof *tmp);
+         memcpy (tmp, to, LFACE_VECTOR_SIZE * sizeof(*tmp));
 
          merge_face_ref (w, f, from[LFACE_INHERIT_INDEX],
                          tmp, false, named_merge_points, attr_filter);
@@ -2177,7 +2182,8 @@ merge_named_face (struct window *w,
                     && !UNSPECIFIEDP(from[attr_filter]))
                  || (!NILP(from[attr_filter])  /* Filter, unspecified, but 
inherited.  */
                     && UNSPECIFIEDP(from[attr_filter])
-                    && !NILP (from[LFACE_INHERIT_INDEX]))))
+                    && !NILP (from[LFACE_INHERIT_INDEX])
+                    && !UNSPECIFIEDP (from[LFACE_INHERIT_INDEX]))))
         merge_face_vectors (w, f, from, to, named_merge_points, attr_filter);
 
       return ok;